Research Article Production Cycle for Large Scale Fission Mo ...downloads.hindawi.com/journals/stni/2013/704846.pdfScience and Technology of Nuclear Installations Mix. oxide Charcoal

Hindawi Publishing CorporationScience and Technology of Nuclear InstallationsVolume 2013 Article ID 704846 14 pageshttpdxdoiorg1011552013704846

Research ArticleProduction Cycle for Large Scale Fission Mo-99Separation by the Processing of Irradiated LEU UraniumSilicide Fuel Element Targets

Abdel-Hadi Ali Sameh

Zellmarkstraszlige 7 76275 Ettlingen Germany

Correspondence should be addressed to Abdel-Hadi Ali Sameh aasamehgmxde

Received 16 June 2013 Accepted 20 July 2013

Academic Editor Mushtaq Ahmad

Copyright copy 2013 Abdel-Hadi Ali Sameh This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Uranium silicide fuels proved over decades their exceptional qualification for the operation of higher flux material testing reactorswith LEU elements The application of such fuels as target materials particularly for the large scale fission Mo-99 producersoffers an efficient and economical solution for the related facilities The realization of such aim demands the introduction of asuitable dissolution process for the applied U

3Si2compound Excellent results are achieved by the oxidizing dissolution of the

fuel meat in hydrofluoric acid at room temperature The resulting solution is directly behind added to an over stoichiometricamount of potassium hydroxide solution Uranium and the bulk of fission products are precipitated together with the transuraniumcompoundsThe filtrate contains the molybdenum and the soluble fission product species It is further treated similar to the in-fullscale proven UAl

119909process The generated off gas stream is handled also as experienced before after passing through KOH washing

solutionThe generated alkaline fluoride containing waste solution is noncorrosive Nevertheless fluoride can be selectively bondedas in soluble CaF

2by addition of a mixture of solid calcium hydroxide calcium carbonate to the sand cement mixture used for waste

solidification The generated elevated amounts of LEU remnants can be recycled and retargeted The related technology permitsthe minimization of the generated fuel waste saving environment and improving processing economy

1 Introduction

Particularly for the large scale producers the conversion ofthe production targets for fission Mo-99 presents a seriouschallenge for keeping economical conditions for operatingtheir plants The uranium enrichment dropping from sim90to sim198 demands modifications on process operation tocompensate for the resulting loss in output Evaluations basedon keeping the production process proven since decadesunchanged and just increasing the amount of processedtargets are not realistic in general The dominant reasons arelimitations on efficient irradiation positions in the availableresearch reactors plus drastically increased processing andwaste costs

The idea of maintaining the current production process[1ndash8] by increasing fuel densities of the targets exploitingthe progress in target technology from actually sim1 gUcm3

for highly enriched uranium (HEU) to approximately26 gUcm3 for low enriched uranium (LEU) targets can beclassified as a compromise Such compromise is appropriatefor several small- and medium-scale facilities but not forlarge scale producers of batch sizes in the average of 4000Ciof Mo-99 at End of Production (EOP) When keeping thesame amount of targets the predictable loss of producedactivity will bemdashunder optimal conditionsmdashmore than 30The described drawback can be prevented by applying LEUtargets of factor 5 higher fuel contents than the actual HEU-based targets Actually that condition can be fulfilled by twotypes of targets One of them is made from U-metal foiltightly enclosed in aluminumThe dissolution process relatedto these targets is applying nitric acid respectively low basiccarbonate solution and anodic oxidation of uranium [9ndash11]The other target is manufactured from uranium silicide fuelcladded with aluminum derived from the MTR type fuel

2 Science and Technology of Nuclear Installations

developed for research reactor core conversions Dissolutionexperiments of U

3Si2in alkaline media by H

2O2[12ndash15]

showed promising results on small scale productions whichcould not be confirmed in larger scale Main reason for thatlack of larger scale is the aggressive decomposition ofH

2O2in

presence of the alloy With respect to the experienced prob-lem the process presented below follows another concept

The publication has focused on the processing of irra-diated LEU targets of uranium silicide for the large scaleproduction of fission Mo-99 Silicide targets were favoredbecause of their proven and reliable operation as researchreactor fuels during decades and their commercial availabilityon the world market Moreover the results achieved with thepresented dissolution process [15ndash20] favored that selectionAs the silicide compound is not attacked by caustic solutionapplied for the target digestion a selective dissolution processfor the remaining silicide meat had to be developed Evidentcondition was and still is that the new process steps are fittingto the proven HEU-based production process operating withUAl119909-Al targets fromHEU Originally the up-to-date process

was developed and operated at KFK as an integral partof a closed cycle Figure 1 shows the scheme of the UAl

119909

production cycleThe part of that process related to the Mo-99 separation

and the off-gas handling technology is actually operated attheMallinckrodtMedical Facility at PettenTheNetherlandsFigure 2 shows a simplified scheme of the process operating atPetten It was established there by a licensing and know-howtransfer agreement contracted with KFK The Petten facilityis producing approximately 25 of the world market whichis estimated to be 12000 Ci 6 days precalibrated weekly Theoperation reliability and the environmental impact of thisinstallation are exceptional worldwidewith an average annualrelease of 73 times 1011Bq of Xe-133 All data mentioned abovewere investigated respectively determined by the CTBTOand published by PNNL [21]

Already during the development and testing at KFKimplementation of the silicide fuel and related modificationsof the original (UAl

119909) process had to fit to the proven process

concept At KFK the investigation program was successfullycompleted and the processmodifications were demonstratedwith both fitting to a later scale of 1000 6d-Ci Mo-99 atEOP Keeping the proven concept the new process has beenintegrated in a closed fuel cycle That cycle was demon-strated repeatedly The Mo-99 separation process is startedby alkaline digestion of the irradiated silicide targets Theremaining silicide residue is dissolved in hydrofluoric acidunder oxidizing conditions [22 23]

2 Considerations on Processing Operation

21 Uranium Silicide as Target Compound

(i) Processing of irradiated silicide fuels permits theadaptation ofmajor parts of the original HEU processfor the production of fission Mo-99 from irradiatedUAl119909targets The selection of U

3Si2as the fuel com-

pound for the LEU targets had the same backgroundas had the choice of UAl

119909as the fuel compound for

the HEU fuel Both selected target types presentedjust the adaptation of the type of research reactorfuel throughout applied for the relatedU-enrichmentresulting in UAl

119909-based targets for HEU and U

3Si2

based for LEU(ii) Since some decades silicide-based fuel elements are

presenting the standard nuclear fuels for high andmedium flux material test reactors (MTRs) That fuelcombines high fuel density with high thermal anddimensional stability and provides operations safetyup to burn up of around 80 [15 17 19]

(iii) Already the regularly applied standard uranium den-sity of U

3Si2fuel of 48 gUcm3 permits full compen-

sation of the uranium content originating from theconversion from HEU to LEU for fuel elements aswell as for irradiation targets

(iv) Claddingmaterial and dimensions of theU3Si2-based

LEU targets are very similar to the processed UAl119909-

based HEU targets That fact prevents expensivemodifications of the proven hardware devices used forcarrying out the reactor irradiations and handling theproduction targets in hot cells

(v) The potential of silicide fuels enables the productionof fuel elements and irradiation targets of even higherU-densities up to 58 gUcm3 Such fuels were pro-duced from the same named compound andwere alsosuccessfully irradiated to average burn-ups of above50 without any deviation in their dimensional andthermal stability [18ndash20] The potential for higher U-loading is of relevance with respect to future recyclingof the uranium from spent targets and retargeting ofthe purified fissionable material

(vi) From economic point of view recycling and retarget-ing are essential particularly for large scale producers

22 Evaluations of Dissolution Process The dissolution ofthe short-time cooled irradiated targets presents a sensitiveoperation step regarding the high inventory of volatile andradio-toxic fission nuclides contained in the fuel matrix(meat) Operational safety and public acceptance concernsdemand the minimization of the potential contamination aswell as hazards from emissions of volatile fission productsinto the environment Most efficient precaution measureis the implementation of advanced processing and off-gashandling technologies Both measures are interacting witheach other Essential precondition for the minimized releaseof iodine is the exclusion of any acidic operation as long asiodine activity is in the system Another concern is relatedto elevated releases of the isotopes Xe-133 and Xe-135 tothe environment The most efficient and economical way ofhandling those issues is applying a combination of advancedprocess operation technology and efficient xenon retentionrespectively delay on charcoal columns For safety reasonsany application of charcoal filters is strictly prohibiting thepresence of nitrogen oxide in the off-gas stream Thusany dissolution of irradiated fuel in nitric acid would bemost critical as nitric acid is always accompanied by NO

2

Science and Technology of Nuclear Installations 3

Mix

oxi

de

Char

coal

Char

coal

Char

coal

To cellventilation

H2Ocond CuO

Vacuumtank Dissolver

Iodineseparation

AG1times

8

MnO

2

Chel

ex-100

AG1times

4 Sub

I131prod

prod

TransportIrradiation

FE production

UAl3 UF4 U3O8

WasteWaste

Waste Waste Waste

TBP

Iodinepurificproc

Bio-

Rex5

Mo-99

(NH4)2U2O7

Figure 1 Production cycle of HEU-based UAl119909- plate-type targets

Irradiation

Recyclingand

retargetation

Waste tanks

Vacuumtank

CuOoven

Dissolver

I-se

para

tion

AGI

U

U + FP

U + Mo-99Mo-99

+ FP

Filters Ventilation system

Chel

ex

AGI

1 2 3 4

Subli-mationM

nO2 Activity

measurementdispensing

Decontaminationand

final treatment

Figure 2 Schemes of the HEU-based fission Mo-99 production process from irradiated UAl119909targets


permanently generated during such operation by radiationdegradation of HNO

3

The described drawbacks are major reasons for a strongpreference for the alkaline processing starting by the alkalinedigestion of the target The digestion is fully sufficient to getthemolybdenum into solution as it is attacking the aluminidecompound Subsequently the silicide is dissolved by anoxidizing acid treatment at room temperature The selectedsolvent HF is proved to be efficient as well as excellent tohandle by using related proven materials inside the hot cellsuch as Hastelloy Hastelloy has been applied for the produc-tion of hundreds of tons of HF per year by chemical industryThe described drawbacks of applying HNO

3accompanied

by its degradation products are prevented by the KFK-developed processing system As HF is one of the mostresistant chemicals it is not decomposing by radiation and itis excellent to be washed out of the off-gas stream by passingthrough a solution of KOH The dissolution process iscarried out at room temperature within 60 minutes In thesubsequent purification process the acidic solution has not tobe handled as it is converted to alkaline after the dissolutionstep Fluoride anions in the alkaline solution are neithercorrosive nor disturbing the following purification of theproduct stream Further fluoride anions in the alkalinemediaare not disturbing the Mo-retention on the anion exchangerAG1 (see Figures 1 and 2) Nitrates as added by someproducers to the digesting solution are the blocking highlyefficient and economical purification systems such as AG1and Chelex-100 To prevent hydrogen formation during thealkaline digestion step of the aluminum alloy of the targetcladding and the UAl

119909meat in some processes nitrate is

addedThe alternative hydrogen oxidation towater on copperoxide as applied at KFK never created any problem withall users For the described reasons all large scale producersincluding the Petten facility never added nitrate to the causticsolution A final aspect of the KFK designed and developedprocessing is related to the waste treatment For the silicideprocess the alkaline waste stream is solidified in cementsimilar to the comparable UAl

119909process In case of the silicide

dissolution the fluoride content in the alkaline solution ismdashwith solid mixture of Ca(OH)

2and CaCO

3added to the

cementmdashforming insoluble CaF2

Back to the dissolution part of the processing both thedigestion of the target and the subsequent HF-dissolutionstep are operated in a Hastelloy dissolver The filtration unitconnected to the dissolver is also made from Hastelloy TheMo-separation process is started by the alkaline digestion ofthe aluminum cladding (preferably ldquoAlMg1rdquo) together withAl-matrix of the meat the fueled part of the target in6M KOH Aluminum and the fission products located atthe surface of the insoluble silicide particles are dissolvedThese are mainly cesium strontium iodine molybdenumand small contaminations of other fission products such aslanthanides ruthenium and zirconium The off-gas of thealkaline digestion contains hydrogen generated by the alu-minum dissolution to aluminate and the magnesium con-version to the hydroxide together with approx 10 of thenoble gas activity The major radioactivity of the gas streamis originating from Xe-133 and Xe-135 The noble gases

leave the dissolver together with the hydrogen at its upperend driven by helium or nitrogen gas which is constantlymetered into the dissolver Hydrogen is oxidized to water viaa copper oxide ldquoovenrdquoThat oven is a heated device containingCuO The formed water steam is condensed in a relateddevice Xenon is collected together with the driving gas inpreevacuated stainless steel tanks and pumped into a xenondelay section later on passing cooled deep bed carbon filterson its way The described operation which is similar to theUAl119909digestion is schematically presented in Figure 3

The filtrate of the alkaline digestion contains approx 10of the Mo-99 generated by fission together with the relatedsoluble fission-generated nuclides To collect the includedMo-activity the filtrate is undergoing the same purificationprocedure as the molybdenum bulk later on Therefore thefiltrate is fed through a floating silver oxide column whereiodine is retained Figure 4 is showing a simplified scheme ofthe iodine separation on this advanced system The namedcolumn is located above a stainless steel (SS) device providedwith a filtration and collecting unitThe column is connectedwith the device below by an SS-valve That valve to the vesselis closed during feeding the process solution After endingloading of the iodine containing solution the valve to thevessel is opened The floating silver oxide is washed into thevessel The collected silver oxide is reduced to silver by asolution of H

2O2 The previously retained iodine remains

loaded over silver metal as silver iodide It can be stored forsafe iodine decay or further used for the separation of I-131on commercial base

The passing through solution which contains the Mo-activity is loaded on the strongly basic anion exchangerAG1 The operation step described in the previous sectionis repeated with the alkaline bulk resulting from the silicidedissolution The Mo-bulk is also fed through the sameAG1 column after completion of the above described iodineseparation step on silver oxideThe eluate of AG1 contains thecombined two Mo-streams In order to improve the purifi-cation efficiency and to reduce the amount of higher activesolid waste the AG1 operation is split into two AG1 columnsconnected and acting behind each other The first AG1 ismade of stainless steel and the second being a larger columnis of propylene (PP) As experienced contaminants (on topof all iodine) and soluble ruthenate compounds reduced toruthenium dioxide on the organic resin are retained at theentering side on the first column Molybdenum is movedby the alkaline process solution and the following washingKOH solution through the first column to the second andlarger column connected behind After disconnecting of thefirst column being loaded with contaminants the elutionof molybdenum from that second column is initiated Withrespect to the minimization of higher active waste the smallcolumn is made of stainless steel to permit long-term radi-ation resistant storage of the tightly enclosed contaminantsThe larger column behind is of PP It is cheaper to purchaseand far more economical to treat as waste The experienceachieved with this modification is highly positive from allsides The same concept is applied by the final AG1 system(see Figure 2) as the potential contamination hazard is verylow Here the entering small column is of PP already


Proc

ess

start

evac

uatio

n

Coo

ling

Coo

ling

Coo

ling

Coa

l filte

r

Wat

erco

nden

ser CuO

oven

VT1

VT2

VT3

SVT

Dropletcollector

Dissolver

Chem

ical

solu

tions

Cell 2

Iner

t gas

ldquoheli

umrdquo

Figure 3 Treatment of the off-gas generated during alkaline digestion of U3Si2and AlMg1-cladding

MoIodine

Feed

AG1

-1co

lum

n

Ag2O

Figure 4 Separation of iodine on the floating silver oxide column

23 Dissolution of Silicide Meat in HFH2O2 The silicide

particles of the meat remaining on the sinter metal filter aredissolved in sim6M HF under catalyzed oxidation conditions[23] The oxidation agent is hydrogen peroxide Suitablecatalytic agents are KI KBr and KCl or higher oxidationstates of halogen compounds such as hypochlorite hypo-bromite or KIO

3 The dissolution is carried out at sim20∘C

The oxidation agent is needed to oxidize the primary formed

insoluble layer of UF4to soluble UO

2F2 The oxidation with

H2O2in absence of the catalyzing agent is inefficient because

a major amount of the H2O2is just decomposed without

significant impact Fully different is the situation in presenceof the mentioned halide compounds All these compoundsare oxidized by H

2O2which acts as strong oxidizing agent in

acidic solutionsThe following formula and the related redoxpotentials underline the oxidation efficiency of hydrogenperoxide in acidic media

Redox potentials of H2O2and related catalysing com-

pounds used for the oxidation of UIV to UVI and its solutionin hydrofluoric acid

U4+ + 2H2O 999447999472 UO

2

2++ 4H+ + 2e + 0338V

H2O2+ 2H+ + 2e 999447999472 2H

2O + 177V

Clminus +H2O 999447999472 HClO +H+ + 2e + 150V

Brminus +H2O 999447999472 HBrO +H+ + 2e + 133V

I +H2O 999447999472 HIO +H+ + 2e + 099V

(1)

The oxidized halogen compounds oxidize efficiently UF4 tosoluble UO

2F2following the chemical formula

UF4+HIO 997888rarr UO

2F2+HI + 2HF (2)

The complete dissolution formula for the silicide alloy is

U3Si2+ 18HF + 6H

2O2997888rarr 3UO

2F2+ 2H2SiF6+ 6H2

(3)

Following the formula 18 moles of HF is needed for thedissolution of 7685 g of the alloy A full scale productionof about 4000Ci at EOP demands around 200 g of 1975


enriched U3Si2 assuming similar irradiation conditions as

applied for an equivalent amount of HEU 93 enrichedThe dissolution of the HEU-related amount demands far lesshydrofluoric acid

The dissolution of the silicide is completed within sim60minutes The solution is pressed through the sinter metalfilter and fed in to an over stoichiometric amount of sim8MKOH solution The KOH excess is adjusted to a final totalmolarity of sim3MKOH Uranium is precipitated as potassiumuranate together with the insoluble hydroxides and oxidehydrates of the related fission products and higher actinidesThe alkaline filtrate contains all in the fuel still remainingMo-99 activity This amount presents 90 of the in total byfission generated Mo-99 activity The solution also containsthe related soluble fission products iodine cesium partiallystrontium and contaminants of further fission productsmainly ruthenium and antimony

The above described HF treatment is operated in Hastel-loy devices Also the acidic filtrate is fed through a Hastelloypipe in to the precipitation vessel below the surface of theKOH solution All tubes used for feeding the acidic solutionare treated behind with alkaline solution All operationsunder alkaline conditions are carried out in stainless steeldevices

The uranium precipitate is boiled for 20 minutes toinsure the decomposition of the formed soluble peroxidecompounds of uranium The Mo-containing filtrate is fedthrough the floating silver oxide column as described before(see Figure 4) The filtrate of the formed AgAgI

minusprecipitate

is fed through the same AG1 column which the first 10 ofgenerated Mo had been loaded on The described operationand the specific treatment of the dissolver exhaust gases bothduring the HF operation [23] are schematically presented inFigure 5

24 Elution of the AG1 Column The loaded AG1 is washedby minimal 3-column volumes of 3M KOH to ensureefficient replacement of the fluoride anions The resin bedis emptied from residual amounts of the KOH solution bypassing air through The elution is initiated by a solution of1M NaOH and 2M NaNO

3 The solution is fed from the

bottom to the top of the column to achieve optimal contactbetween eluent and resin The introduction of nitric acid andnitrate ensures excellent elution yields for this operationThepositive influence of nitrate on the Mo-elution from AG1turns to the negative for the subsequent purification step onChelex-100 Thereto molybdenum is loaded on Chelex-100from a reducing and complex forming media Nitrate mustbe avoided in the whole system by loading of the cationicmolybdenum compounds on a stationary phase followed bywashing out the NO

3

minusHNO3

25 Mo-Loading on Hydrated MnO2and Dissolution of the

Loaded Matrix The eluate of the AG1 column is acidified byHNO

3to a final acidity ofsim1molarThe adjustedMo-solution

is fed through a column of hydrated MnO2 Molybdenum is

retained as cationic molybdenyl compound on the inorganicexchanger The Mo-loaded stationary phase is washed with

a solution containing sim001M K2SO4 The amount of the

washing solution is adjusted such that the passing throughsolution is free of nitrate The addition of K

2SO4is needed to

stabilize the lattice of the MnO2matrix by the larger potassi-

um cationThe introduction of the MnO

2column offers additional

benefits on top off all the concentration of molybdenum andcompact feed for the following purification stepThe purifiedproduct is released from the column free of losses by a uniqueoperation [24]Thereto the loadedmatrix is directly dissolvedin the feeding solution prior to the subsequent purificationstep on Chelex-100The resulting solution consists of sulfuricacid thiocyanate sodium sulfite and potassium iodide Thefinal molarity of the major compound is sim2MH

2SO4Under

these conditions the molybdenum is reduced and forms theextremely stable anionic complex [Mo(SCN)

6]minus3 The Mo-

complex is retained on Chelex-100 with a distribution coef-ficient of about 5 times 104 In absence of the exchanger Mo-compounds of different oxidation stages below 6 are formedIn presence of the exchanger the equilibrium is moved to thecomplex of the highest negative charge This compound isthe red [Mo(SCN)

6]minus3 complex Higher Mo-oxidation stages

have lower specific electrical charges When the preferredcompound is retained on the matrix the dynamic equilib-rium is moving in the described direction

26 Purification on Chelex-100 Column The purification ofmolybdenum on Chelex-100 offers outstanding decontami-nation efficiency [25]

This fact is underlined by the extremely high distributioncoefficient for molybdenum thiocyanate compound on theresin of around 5 times 104 while the distribution coefficients ofthe related fission products species are in the average of 1 [4]Most relevant for this part of operation are contaminations oflanthanides ruthenium and zirconiumThe realized separa-tion factors for the mentioned contaminations are sim104

27 Final Chromatographic Purification on AG1 Column Thefollowing operation is introduced as a preparatory step forthe sublimation of MoVI oxideThe sublimation presents theultimate purification of the product from organic and inor-ganic impurities

Organic impurities are originating from flexible connect-ing tubes and applied organic exchangers Such impuritiespresent potential reducing agents and are the cause for lowerelution yields of technetium from the generators at a laterstage

Inorganic impurity traces of iron nickel cobalt andchromium are brought in the product solution by appliedmetallic hardware componentsThe presence of such impuri-ties in the final product is themajor reason for elevated break-through of molybdenum during loading and elution of theTc-generator columns Such phenomenon can be explainedby the instability of the related cations under low acidicloading and almost neutral pH-values during elution of thegenerators The formed colloids in the solution adjusted forgenerator loading retain the molybdenum compounds on


Safe

ty v

ac t

ank

H2-oxid

KOH

KOHKOH

HFaddH2O

DissolverFuel

precipi-tation

Xenon separation

HF

was

h

Mo-99-process stream

HeN2HeN2

Figure 5 Combined operation of U3Si2dissolution and precipitation

their surface and pass loadedwithmolybdenum through thegenerator column

The gradual thermal treatment of the dried product of upto sim1000∘C at which the sublimation is completed decom-poses the organic compounds and converts the inorganicimpurities to the insoluble and chemically resistant so-calledhighly burned oxidesThe oxides remain in the crucible whilemolybdenum oxide is sublimated The resulting productshows excellent behavior during transportation of the bulksolution to the users and on the generators

The sublimation step demands the preseparation of themajor bulk of the cations mainly of sodium from the Mo-containing solution The presence of sodium in the Mo-solution would lead to the formation of mixed oxides withmolybdenum The volatilization of MoVI-oxide from suchcompound demands for higher temperatures than salt-freesystems The purification of the Mo-solution is achieved byloading of molybdenum on an AG1 column The stationaryphase is washed by feeding of the sufficient amount of waterthrough its resin bed

The molybdenum elution is carried out by slow meteringof highly pure 2ndash4M HNO

3through the column

28 Sublimation of MoVI-Oxide and Final Product Prepara-tion The nitric eluate is filled into a platinumiridium cru-cible and evaporated to dryness The operation is carried outin controlled ventilated quartz equipment The acid vapor isdriven out of the evaporation equipment by a metered nitro-gen gas streamThegas stream is directly fed throughwashingdevices to prevent the contamination of the cell environmentwith acid and nitrogen oxide After completed evaporationthe crucible with the included dried MoVI-nitrate is placedin the quartz sublimation device The complete unite is thenplaced into the sublimation oven The temperature in the

oven is gradually increased up to sim1000∘C The sublimatedMo-oxide is collected in the quartz condenser above thecrucible The sublimation device is taken out of the oven forcooling in cell atmosphere After a cooling time of sim15minthe condensed Mo-oxide is dissolved in ammonia solution

TheMo-solution is transferred into a round bottom flaskAfter adding a mixture of sodium hydroxide and sodiumnitrate as calculated for the amount of final product theammonia is trapped out by smooth boiling Both compoundsare added to the final product solution to stabilize themolybdate in the high active solution and to prevent the pre-cipitation of Mo-compounds of lower oxidation level mainlyconsisting of hydrated MoO

2 The addition of nitrate is also

recommended to reduce the amount of hydrogen generatedby radiation degradation of water in the product flask Thenitrate anions act as a radical catcher for hydrogen radicalsforming nitrite anions and water

29 Recycling of Uranium from the Spent Fuel Residue Theuranium recycling process is initiated by dissolution andpurification of the uranium stored in the collecting sintermetal filters Those filters carry about 98 of the initiallyirradiated uranium as alkali uranate together with theinsoluble fission products and the transuranium elementsThe U-decontamination is carried out after an approximatecooling time of 6 months During this period U-237 and theshorter living fission products have decayed The remainingradiation dose of the residue is mainly caused by the fissionproduct nuclides ruthenium zirconium niobium and thelanthanides The residue includes also the generated pluto-nium as oxideoxide hydrate The dissolution concept aimsfor the selective dissolution of uraniumby keeping the bulk ofthe activity carriers and particularly plutonium in the residue


According to those considerations a suitable processwas developed and demonstrated at KFK [26] The processis based on the basic dissolution of uranium by forma-tion of the soluble anionic uranyl-tricarbonate complex[UO2(CO3)3]minus4 The dissolution is carried out in hydrogen

carbonate carbonate or mixed solutions of both Hydrogenperoxide is added to the solution for the oxidation of U-species of lower oxidation stages potentially formed by radi-ation The dissolution is carried out at temperatures between20 and 40∘C Figure 6 shows the dissolution behavior ofammonium diuranate as a function of CO

3

minus2 concentrationFigure 6 delivers the maximum uranium solubility of this

system being at 48 gUL For practical operation conditionsa U-solubility of 40 gUL should be considered The limitedsolubility of uranium in theHCO

3

minusCO3

minus2 is by far overcom-pensated by the achieved advantages which are as follows

(i) Efficient decontamination of the uranium streamalready by the dissolution process in contradiction tothe common fuel dissolution in nitric acid in whichthe uranium and nearly the whole contaminants aredissolved The realized decontamination factors foruranium in the hydrogen-carbonatecarbonate sys-tem are in the average of 100The high separation effi-ciency also includes the decontamination from thegenerated transuranium elements neptunium andplutonium Both are retained in the residue when thebasic solution is boiled for 30 minutes

(ii) Safe processing conditions such as carbonate solu-tions being absolutely noncorrosive and requiringuncomplicated off-gas treatment measures only

(iii) Quick and economical predecontamination of theuranium stream on compact radiation resistant inor-ganic adsorbers

210 Chromatographic Decontamination of the Uranium Tri-carbonate Stream In spite of the high decontamination ofuranium by the carbonate dissolution fission product car-bonate ions are codissolved Possibilities for their pre-sepa-ration on selective radiation-resistant inorganic exchangers[26] were experimentally investigated Static distributionexperiments of the relevant fission nuclide ions on inor-ganic exchangers showed promising separation options forcarbonate media The preselected exchangers were furthertested under dynamic conditions in absencemdashand later onalso in presencemdashof uranium in the solutionThedeterminedretention efficiencies of the relevant fission nuclides on theinvestigated exchangers are composed in Table 1 The reten-tion efficiencies of the related fission products on the differentcolumns are expressed in of the original activity in thesolution

The data above show the efficiency of several inorganicexchangers for the separation of the investigated fissionproducts in this system Regarding these data ruthenium isnot completely retained on the related exchangers only Thesuccessful adaptation of these promising systems under realprocess conditions depends on further information such as

Table 1 Dynamic retention behavior of fission product traces oninorganic exchanger columns loading solution 10mL washingsolution 15mL total HCO

3

minusCO3

minus2content 1M column diameter97mm bed volume 55mL adsorber weight 5 g loading speed30 cvh

Fiss Prod Ce Cs Ru Sb Sr ZrAl2O3 100 60 94 38 100 0MnO2 100 7 82 100 100 100SnO2 95 0 6 0 100 63

60

50

40

30

20

10

0

0 1 2 3

(gU

L)

MCO3

minus2

Figure 6 Dissolution of ammonium diuranate at varying CO3

minus2

concentrations

the specific retention capacity of each nuclide in presence ofuranium under real operation conditions

Figure 7 shows the corresponding data for cerium onMnO2as the stationary phase Ce-141 being added as an

indicator The figure shows the high efficiency of hydratedMnO2as a matrix for the chromatic separation of cerium

from hydrogen-carbonatecarbonate containing solutionsComparable data were achieved for the other fission

nuclides All except ruthenium could be separated at one stepon MnO

2columns The deviating behavior of ruthenium is

related to its ability to form varying complexes simultane-ously Even in presence of an adsorber retaining the preferredcomplex the equilibrium adjustment is too slowly

Interesting is the observed increase of the fission productretention in presence of uraniumThemost probable explana-tion for this behavior is the decrease in concentration of freeHCO3

minusCO3

minus2 ions caused by the complex formation withuranium Higher HCO

3

minusCO3

minus2 concentrations lead to theformation of negative charged fission product ions which arenot retained on the adsorberThe reduced retention efficiencyof ruthenium is also improved by the presence of uraniumin the system but still remains lower than of all nuclidestested for the data of Table 1Therefore additional purificationsteps are needed for the complete decontamination of theprocess stream from the rest activity of ruthenium remainingin the solution The deviating behavior of ruthenium is also


10

20

30

40

50

60

70

80

90

100

Loading Washing

20 40 60 80 100 20 40 60 80 100

(mL)

Ce-144B(

)

Figure 7 Breakthrough of cerium during the loading and washingon hydrated MnO

2column from hydrogen-carbonatecarbonate

containing solution HCO3

minusCO3

minus2 ratio 955 total molarity 1Mcerium-concentration 1mgL U-concentration 35 gL columninner diameter 97mm bed volume 55 mL adsorber weight 55 gMnO

2 and loading speed 30 cvh Ce-141 was added to the loading

solution as a radioactive indicator

100

80

60

40

100 200 300 400

Resin (gUkg)

R(

)

Bio-Rex5

Figure 8 U-loading on Bio-Rex5 U 1 3 HCO3

minusCO3

minus2

experienced in different systems for example nitric acid Inthe latter 21 species of ruthenium were determined anionicneutral and cationic The latter is a reason too that thecomplete separation of ruthenium demands a series of steps

211 Uranium Concentration and Final Purification Thedecontaminated fuel solution still has to undergo a finalpurification process in which the alkaline salt content andthe still remaining fission product nuclides are separatedUnder such conditions best results are achieved by theproven PUREX-process [27 28] Uranium is extracted fromnitric acid solution in tributyl phosphate Optimal extractionconditions are obtained by the extraction of uranium fromapproximately 3M HNO

3in an organic phase containing

30 vol TBP in kerosine The liquidliquid extraction system

100

80

60

40

20

1 2 3

Column volume [U]

Bio-Rex5

EU

Figure 9 U-elution with 4M HNO3

Brea

kthr

ough

()

100

80

60

40

20

00 1 2 3 4 5 6 7 8 9 10

Loadingflowrate

Column volume [I]

Breakthrough after washingCe-144 994Cs-137 999Nb-95 990Zr-95 994

Ru-106 994Sb-125 1000Uran 38

Elution(002m HNO3)

Washing(3m HNO3)

Figure 10 Decontamination of uranium from fission product spe-cies on TBP loaded SM-7 column

is the best solution formiddle to large scale batches and can beoperated continuously The situation is different for the recy-cling of the U-batches needed for Mo-99 production targetsBatch sizes of 1000 g are optimal to be operated in laboratoryscale The most practical operation is achieved by using thesolid-bed extraction technique [29 30] It is based on theextraction ofUO

2(NO3)2dissolved in nitric acid in undiluted

TBP TBP is loaded on a macroporous nonpolar matrix ofpolystyrene-divinyl benzene such as Bio-Beads SM-2 andSM-4 (Bio-Rad Richmond VA USA) or on the intermediate


Figure 11 Side view of the fuel rectangle

Figure 12 Surface view of the fuel rectangle

polar acrylic ester matrix SM-7 (Bio-Rad) The describedtechnique combines the high decontamination efficiency ofthe TBPHNO

3system with the simple handling of chro-

matographic operations Favored operation conditions forthe solid bed extraction are achieved from feed solutions ofhigher U-concentrations Under such conditions the extrac-tion of contaminants such as ruthenium and zirconium isefficiently reduced As previously described the U-solubilityin carbonate solutions is limited to 45 gUL Optimal decon-tamination of uranium on TBP loaded solid-bed columns isachieved at U-concentrations in the average of 200 gL Suchconditions are realized most practical by loading of the U-tricarbonate species on the intermediate basic exchanger Bio-Rex5 (Bio-Rad) which permits the loading of approx 300 gof uranium on 1 kg of the resin The elution is carried outby 4M HNO

3from the bottom to the top of the column

to prevent overpressure formation by the released CO2 The

eluent acid concentration also presents the optimal loadingHNO

3molarity for the solid-bed extraction Figure 8 shows

the U-loading on Bio-Rex5 from the carbonate solutionFigure 9 shows the U-elution with 4M HNO

3from the Bio-

Rex5 The elution with 4M HNO3considers acid losses by

adsorption during elution of the exchanger resulting in anapproximate HNO

3molarity of 3 in the U-eluate presenting

the optimal molarity for the solid-bed extractionSubsequently the U-containing nitric acid solution is

fed through the TBP loaded solid-bed column Uraniumis extracted under the optimized loading conditions as asharp yellow band on the stationary phase while the fissionproducts leave the column at the upper endAfterwashing thestationary phasewith 3MHNO

3 uranium is eluted by 002M

HNO3 Figure 10 shows typical solid-bed extraction curves

Figure 13 Preparation of the uranium silicide target plate

for uranium and potentially accompanying fission productson a TBP loaded SM7 column

Uranium is precipitated by ammonium hydroxide Theammonium diuranate precipitate is centrifuged dried andfinally calcined at 800∘C to U

3O8

212 Preparation of the Uranium Silicide Alloy The uraniumoxide is transferred to a nickel crucible and converted to UF

4

by treatment with a gas mixture of hydrogen and hydrogenfluoride in argon atmosphere at 650∘C The reaction isperformed in a nickel oven The UF

4-powder is transferred

to KUF5by melting the tetrafluoride with the stoichiometric

amount of potassium fluoride in the same oven at 850∘CTheconversion to KUF

5is carried out in argon atmosphere in

a graphite crucible The product is powdered and added insmall portions to a melting electrolysis bath of a salt mixtureof 50 weightNaCl and KCl in which the graphite crucible isacting as anode A molybdenum sheet is used as the cathodeThe process is carried out in argon atmosphere at 800∘CTheU-loaded cathode is replaced frequently and washed aftersubsequent coolingwith ethyl-alcohol containing fewpercentof water and cold water to dissolve the uranium accompa-nying salt in an ultrasonic bath The described procedureis carried out in argon atmosphere The dried U-powder isfinally melted in argon atmosphere under low pressure withsilicon to U

3Si2 The melting procedure is carried out in a

high-frequency oven at 1850∘C

213 Fuel Targeting The alloy is transferred into a glove boxline in which the U

3Si2is grounded in a hard metal swinging

mill All following operations up to the fuel meat encapsula-tion are carried out in argon atmosphere The milled alloy issieved Only particles with grain sizes below 40 micrometerswere mixed with aluminum powder of the same particle sizeAliquots of this mixture are pressed to rectangles which willpresent the meat zone in the final plate Figures 11 and 12show photographs of formed rectangles from 2 directionsFigure 13 shows the target preparation steps starting by theformed rectangle


Mix

oxi

de

Char

coal

Char

coal Cu

O

Vacu

um ta

nk

Dissolver

Iodineseparation

AG1times

8

MnO

2

Chel

ex-100

AG1times

4 Sub

I131prod


FE production

UF4 U3O8

WasteWaste

Waste Waste Waste

TBP

Iodinepurificproc

Bio-

Rex5

prodMo-99

Chimney

U-metal

U3Si2

(NH4)2U2O7

Figure 14 Simplified scheme of the U3Si2production cycle

Figure 15 Irradiated silicide-based fuel targets prior to starting thedissolution process at KFK

Each rectangle (meat) is placed into a suitable frame ofan aluminum-magnesium alloy for example AlMg1 Thenthe combined frame + meat is covered on both sides withplates of the same alloy The package is riveted together andstepwise rolled to the final thickness Before each rollingstep the fuel package is heated up to 400ndash450∘C before eachrolling step The fuel zone is marked under an X-ray screenAfter cutting to the final shape surface treatment completesthe manufacturing Figure 13 depicts the parts and steps oftarget manufacturingThemanufacturing technology followsrelated experiences at KFK [31 32]

Figure 16 Dissolution cell and the applied hardware devices forprocess operation at KFK

214 Target Irradiation and Processing Hundreds of targetswere produced from natural uranium in order to develop andverify production technique and fulfillment of the requiredquality standards The target qualification standards wereidentical to those of regular MTR-fuel elements qualificationstandards

Fuel densities were varying between 15 and 50 gUcm3Natural uranium targets were also used for the developmentand cold testing of the new silicide treatment process Theuranium precipitates generated by cold testing have beenrecycled The prepared silicide fuel was applied for the


Target digestion in NaOH

Filtration Filtration

Filtration

Filtration

Filtration

Residue oxidisingtreatment NaOH + H2O2

Solution transferto precipitation vessel

Mo-purificationprocess


Cladding digestion in KOH

Silicide dissolutionin HFH2O2catalyst


U3Si2

storage filterU + fiss prod


Residue dissol in HNO3

sim90 of Mo-99

sim10 of Mo-99

sim90 of Mo-99

sim10 of Mo-99

UAlx

Figure 17 Fission Mo-99 production flow sheets for irradiated UAl119909and U

3Si2fueled targets

preparation of new targets again and had to undergo thefuel qualification needed for irradiationThe qualified targetswere again dissolved without being irradiated The materialwas repeatedly recycled and processed

The achieved experience was applied for the preparationof those LEU targets foreseen for irradiation and hot processdemonstrationTheproduced LEU targets comprised varyingdensities up to 50 gUcm3 The U-densities of all irradiatedtargets were 3 gUcm3 The uranium enrichment of thetargets was 1975 It was adjusted by blending of recycledHEU fuel of 91 enrichment with natural uranium Theblending was carried out by adding of a solution of uranylnitrate of the natural uranium to a part of the uranium eluateof the TBP solid-bed column at the end of purification cycleThe mixture was precipitated as ammonium diuranate andfurther treated up to metal as described

The silicide production cycle of Figure 14 was completedby demonstration tests at KFK operated at 1000 Ci of Mo-99 at EOP Figure 15 shows 5 of the used irradiated silicidefuel targets prior to starting the dissolution process Figure 16shows the applied dissolution cell and major componentsof the hardware devices applied for the hot demonstrationoperations

The hot experiments with U3Si2-based targets showed

except the dissolution and the related off-gas handling oper-ations no difference to the processing of the UAl

119909-based

fuels The latter were frequently operated on similar scalefor over 100 production runs The dissolution tests of thesilicide targets showed no difference in solubility betweenirradiated and nonirradiated silicide nor with fuel densitiesvarying from 15 to 50 gUcm3The achieved results were notsurprising as in extensive cold dissolution experiments pure

silicide grains of several millimeters diameter were smoothlydissolved in the developed system

3 Conclusions

The described experiments and related high-active demon-strations underlined the advantage of uranium silicide fuelsas an outstanding target material for the production of fissionMo-99 Silicide targets combine remarkable features predes-tinating them as starting up materials for the large scale pro-duction of fission nuclides when starting from LEU Amongothers these features are as follows

(i) The full compensation of the enrichment drop fromHEU to LEU in the production targets

(ii) Long term proven excellent behavior in irradiationas MTR-fuel which simplifies their acceptance in allinvolved research reactors supplementary

(iii) Qualification on large scale and to high burn-ups asnuclear fuels up to uranium densities of 58 gUcm3which even permits outstanding recycling potentialfor the generated spent fuel

(iv) Reliable and reproducible production quality whichcan be easily supervised with view to settled stan-dards

(v) Contamination and off-gas free handling before start-ing up the chemical process regarding the fact that nomechanical target dismantling is needed

The demonstrated process for the production of fissionMo-99 and the integrated fuel cycle both as described is


designed for the long-term large scale operation Relevantfeatures are as follows

(i) Complete separation of the nuclear fuel from theMo-stream already at the beginning of the separationprocess combinedwith the quantitative retention andthe safe enclosure of the nuclear fuel together with thebulk of fission products

(ii) Exceptional low environmental impact comparable tothatUAl

119909process operating on full scale at PettenThe

Netherlands(iii) Uncomplicated and economical to handle noncorro-

sive and nuclear fuel free alkaline waste(iv) Reliable immobilization of the fluoride content in

the alkaline waste by formation of calcium fluorideduring solidification CaF

2being a mineral ldquofluoriterdquo

of very low solubility(v) Efficiently reduced nuclear waste amounts by recy-

cling and retargeting of the spent fuel(vi) Shorter operation times for the silicide fuel in com-

parison to the processing of similar fuel amountsof UAl

119909 Figure 17 shows the operations needed for

both fuel target types and demonstrates the relatedprocessing schemes for UAl

119909and U

3Si2 In case of

the UAl119909processing the needed final treatment for

safe spent fuel enclosure as diuranate is an additionaloperation but integral part of the silicide processingalready

Acknowledgment

For the preparation of this paper the authour was substan-tially supported by H-J Roegler consulted about all mattersof research reactors and their utilization

References

[1] C J Fallias A More de Westgaver L Heeren J M BaugnetJ M Gandoflo andW Boeykens ldquoProduction of radioisotopeswith BR2 facilitiesrdquo in Proceedings of the BR-2 Reactor MeetingINIS MF 4426 pp 1ndash11 Mol Belgium 1978

[2] R O Marques P R Cristini H Fernandez and D MarzialeldquoOperation and installation for fission for fission 99Mo pro-duction in Argentina Fission molybdenum for medical userdquo inProceedings of the Technical CommitteeMeetingOrganized by theInternational Atomic Energy Agency IAEA-TECDOC-515 pp23ndash33 Karlsruhe Germany October 1987

[3] J Salacz ldquoProcessing of irradiated 235U for the production of99Mo 131I and 133Xe radioisotopes Fission molybdenum formedical userdquo in Proceedings of the Technical Committee MeetingOrganized by the International Atomic Energy Agency IAEA-TECDOC-515 pp 149ndash154 Karlsruhe Germany October 1987

[4] A A Sameh and H J Ache ldquoProduction techinques of fissionmolybdenum-99rdquo Radiochimica Acta vol 41 pp 65ndash72 1987

[5] A Mushtaq ldquoSpecifications and qualification of uraniumalu-minum alloy plate target for the production of fission molyb-denum-99rdquo Nuclear Engineering and Design vol 241 no 1 pp163ndash167 2011

[6] K L Ali A A Khan A Mushtaq et al ldquoDevelopment of lowenriched uranium target plates by thermo-mechanical process-ing of UAl2-Al matrix for production of 99Mo in PakistanrdquoNuclear Engineering and Design vol 255 pp 77ndash85 2013

[7] G Ball ldquoStatus update on the 99Mo HEULEU conversion inSouth Africardquo in Proceedings of the NNSA 2nd Mo-99 Top-ical Meeting on Molybdenum-99 Technological DevelopmentChicago Ill USA April 2013

[8] M Druce ldquoManufactoring Mo-99 from LEU for Australianmarketrdquo in Proceedings of the NNSA 2ndMo-99 Topical Meetingon Molybdenum-99 Technological Development Chicago IllUSA April 2013

[9] G F Vandegrift J L Snelgrove S Aase M M Bretschner andB A Buchholz ldquoConverting targets and process for fission-product 99Mo from high to low enriched uraniumrdquo IAEATECODOC 1997

[10] J Jerden J Baily L Hafenrichter and G F Vandegrift ldquoFull-scale testing of the ambient pressureacid-dissolution front-end process for the current Mo-99 recovery processrdquo ChemicalScience and Engineering In press

[11] A Guelis G Vandegrift and S Wiedmeyer ldquoUranium anodicdissolution under slightly alkaline conditionsrdquo ANL ProgressReport Argonne 2012

[12] J D Kwok G F Vandegrift and J E Matos ldquoProcessing oflow-burnup LEU silicide targetsrdquo in Processedings of the 1988International Meeting on Reduced Enrichment for Research andTest Reactors ANLRERTRTM-13 CONF-880221 pp 434ndash442 San Diego Calif USA 1993

[13] Cols P R Cristini and R O Marques ldquoPreliminary inves-tigations on the use of uranium silicide targets for fissionMo-99 productionrdquo in Proceedings of the 1994 InternationalMeeting on Reduced Enrichment for Research and Test ReactorsANLRERTRTM-20Williamsburg Va USA September 1994

[14] G F Vandegrift A V Gelis S B Aase A J Bakel E FreibergY Koma and C Conner ldquoANL progress in developing a targetand process for converting CNEA Mo-99 production to low-enriched uraniumrdquo in Proceedings of the 2002 InternationalMeeting on Reduced Enrichment for Research and Test ReactorsSan Carlos de Bariloche Argentina November 2002

[15] J P Durand Y Fanjas and A Tissier ldquoDevelopment of higher-density fuel at CERCA status as of Oct1992rdquo in Proceedingsof the 1992 International Meeting on Reduced Enrichment forResearch and Test Reactors-Status Roskilde Denmark Sep-tember-October 1992 Argonne National Laboratory ReportANLRERTRTM-19 CONF-9209266

[16] A A Sameh and A Bertram-Berg ldquoHEU and LEU MTR fuelelements as targetmaterials for the production of fissionmolyb-denumrdquo in Proceedings of the 1992 International Meeting onReduced Enrichment for Research and Test Reactors RoskildeDenmark September-October 1992 ArgonneNational Labora-tory Report

[17] J P Durand J C Cottone M Mahe and G Ferraz ldquoLEU fueldevelopment at CERCA-status as of October 1998rdquo in Proceed-ings of the 1998 International Meeting on Reduced Enrichmentfor Research and Test Reactors Sao Paulo Brazil October 1998Argonne National Laboratory Report

[18] A A Sameh ldquoProduction of fission Mo-99 from LEU uraniumsilicide target materialsrdquo in Proceedings of the 2000 Symposiumon Isotope and Radiation Applications Institute of NuclearEnergy Research Lung-Tan Taiwan May 2000


[19] J L SnelgroveQualification Status of 6-GUCm3 U3Si2 Disper-sionTargets for 99MoProduction ArgonneNational Laboratory2011

[20] Workshop on Signatures of Medical and Industrial Isotope Pro-duction (WOSMIP rsquo09) Friuli-Venezia Giulia Italy July 2009PNNL-19294

[21] A A Sameh ldquoKIT Process operating at Petten-the Nether-landsrdquo in Proceedings of the Workshop on Signatures of Medicaland Industrial Isotope Production (WOSMIP rsquo10) Friuli-VeneziaGiulia Italy June 2010 PNNL-21052

[22] A A Sameh and A Bertram-Berg ldquoProcess for treating disso-lution residuesrdquo Patent DE4241955 US5419881 1995

[23] A A Sameh ldquoProcessing and off gas handling of irradiated LEUuranium siliciderdquo in Proceedings of the Workshop on Signaturesof Medical and Industrial Isotope Production (WOSMIP rsquo11)Friuli-Venezia Giulia Italy June 2011

[24] A A Sameh and W Leifeld ldquoProcess for separation of molyb-denumrdquo Patent DE4231955 USA 5508010 1996

[25] A A Sameh J Hoogveldt and J Reinhardt ldquoProcess for recov-ering molybdenum-99 from a matrix containing neutron irra-diated fissionable materials and fission productsrdquo Patent DE2758783 1994

[26] A A Sameh and J Haag ldquoProcess for the separation of largeamounts of uranium from small amounts of radioactive fissionproducts which are present in basic aqueous carbonate con-taining solutionsrdquo Patent DE3428877 USA 4696768 1987

[27] R G Wymer and B L Vondra Light Water Reactor Fuel CycleCRC Press Boca Raton Fla USA 1981

[28] H-J Bleyl D Ertel H Goldacker G Petrich J Romer andH Schmieder ldquoRecent experimental findings on the way to theone-cycle Purex processrdquo Kerntechnik vol 55 no 1 pp 21ndash261990

[29] R Krobel and A Maier International Solvent Extraction Con-ference Lyon France 1974

[30] H Eschrich andWOchsenfeld ldquoApplication of extraction chro-matography to nuclear fuel reprocessingrdquo Separation Scienceand Technology vol 15 no 4 pp 697ndash732 1980

[31] S Nazare G Ondracek and F Thumler ldquoUAl3-Al als Disper-sionsbrennstoff fur Hochstflussreaktorenrdquo KFK 1252 1970

[32] S Nazare Private communication and advice on silicide prepa-ration and targeting (1988ndash1990)

TribologyAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

FuelsJournal of


Journal ofPetroleum Engineering


Industrial EngineeringJournal of


Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

CombustionJournal of


Journal of


Renewable Energy

Submit your manuscripts athttpwwwhindawicom


StructuresJournal of


RotatingMachinery


EnergyJournal of


Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Nuclear InstallationsScience and Technology of


Solar EnergyJournal of


Wind EnergyJournal of


Nuclear EnergyInternational Journal of


High Energy PhysicsAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


developed for research reactor core conversions Dissolutionexperiments of U

3Si2in alkaline media by H

2O2[12ndash15]

showed promising results on small scale productions whichcould not be confirmed in larger scale Main reason for thatlack of larger scale is the aggressive decomposition ofH

2O2in

presence of the alloy With respect to the experienced prob-lem the process presented below follows another concept

The publication has focused on the processing of irra-diated LEU targets of uranium silicide for the large scaleproduction of fission Mo-99 Silicide targets were favoredbecause of their proven and reliable operation as researchreactor fuels during decades and their commercial availabilityon the world market Moreover the results achieved with thepresented dissolution process [15ndash20] favored that selectionAs the silicide compound is not attacked by caustic solutionapplied for the target digestion a selective dissolution processfor the remaining silicide meat had to be developed Evidentcondition was and still is that the new process steps are fittingto the proven HEU-based production process operating withUAl119909-Al targets fromHEU Originally the up-to-date process

was developed and operated at KFK as an integral partof a closed cycle Figure 1 shows the scheme of the UAl

119909

production cycleThe part of that process related to the Mo-99 separation

and the off-gas handling technology is actually operated attheMallinckrodtMedical Facility at PettenTheNetherlandsFigure 2 shows a simplified scheme of the process operating atPetten It was established there by a licensing and know-howtransfer agreement contracted with KFK The Petten facilityis producing approximately 25 of the world market whichis estimated to be 12000 Ci 6 days precalibrated weekly Theoperation reliability and the environmental impact of thisinstallation are exceptional worldwidewith an average annualrelease of 73 times 1011Bq of Xe-133 All data mentioned abovewere investigated respectively determined by the CTBTOand published by PNNL [21]

Already during the development and testing at KFKimplementation of the silicide fuel and related modificationsof the original (UAl

119909) process had to fit to the proven process

concept At KFK the investigation program was successfullycompleted and the processmodifications were demonstratedwith both fitting to a later scale of 1000 6d-Ci Mo-99 atEOP Keeping the proven concept the new process has beenintegrated in a closed fuel cycle That cycle was demon-strated repeatedly The Mo-99 separation process is startedby alkaline digestion of the irradiated silicide targets Theremaining silicide residue is dissolved in hydrofluoric acidunder oxidizing conditions [22 23]

2 Considerations on Processing Operation

21 Uranium Silicide as Target Compound

(i) Processing of irradiated silicide fuels permits theadaptation ofmajor parts of the original HEU processfor the production of fission Mo-99 from irradiatedUAl119909targets The selection of U

3Si2as the fuel com-

pound for the LEU targets had the same backgroundas had the choice of UAl

119909as the fuel compound for

the HEU fuel Both selected target types presentedjust the adaptation of the type of research reactorfuel throughout applied for the relatedU-enrichmentresulting in UAl

119909-based targets for HEU and U

3Si2

based for LEU(ii) Since some decades silicide-based fuel elements are

presenting the standard nuclear fuels for high andmedium flux material test reactors (MTRs) That fuelcombines high fuel density with high thermal anddimensional stability and provides operations safetyup to burn up of around 80 [15 17 19]

(iii) Already the regularly applied standard uranium den-sity of U

3Si2fuel of 48 gUcm3 permits full compen-

sation of the uranium content originating from theconversion from HEU to LEU for fuel elements aswell as for irradiation targets

(iv) Claddingmaterial and dimensions of theU3Si2-based

LEU targets are very similar to the processed UAl119909-

based HEU targets That fact prevents expensivemodifications of the proven hardware devices used forcarrying out the reactor irradiations and handling theproduction targets in hot cells

(v) The potential of silicide fuels enables the productionof fuel elements and irradiation targets of even higherU-densities up to 58 gUcm3 Such fuels were pro-duced from the same named compound andwere alsosuccessfully irradiated to average burn-ups of above50 without any deviation in their dimensional andthermal stability [18ndash20] The potential for higher U-loading is of relevance with respect to future recyclingof the uranium from spent targets and retargeting ofthe purified fissionable material

(vi) From economic point of view recycling and retarget-ing are essential particularly for large scale producers

22 Evaluations of Dissolution Process The dissolution ofthe short-time cooled irradiated targets presents a sensitiveoperation step regarding the high inventory of volatile andradio-toxic fission nuclides contained in the fuel matrix(meat) Operational safety and public acceptance concernsdemand the minimization of the potential contamination aswell as hazards from emissions of volatile fission productsinto the environment Most efficient precaution measureis the implementation of advanced processing and off-gashandling technologies Both measures are interacting witheach other Essential precondition for the minimized releaseof iodine is the exclusion of any acidic operation as long asiodine activity is in the system Another concern is relatedto elevated releases of the isotopes Xe-133 and Xe-135 tothe environment The most efficient and economical way ofhandling those issues is applying a combination of advancedprocess operation technology and efficient xenon retentionrespectively delay on charcoal columns For safety reasonsany application of charcoal filters is strictly prohibiting thepresence of nitrogen oxide in the off-gas stream Thusany dissolution of irradiated fuel in nitric acid would bemost critical as nitric acid is always accompanied by NO

2


Mix

oxi

de

Char

coal

Char

coal

Char

coal

To cellventilation

H2Ocond CuO


Iodineseparation

AG1times

8

MnO

2

Chel

ex-100

AG1times

4 Sub

I131prod

prod


FE production

UAl3 UF4 U3O8

WasteWaste

Waste Waste Waste

TBP

Iodinepurificproc

Bio-

Rex5

Mo-99

(NH4)2U2O7


Irradiation

Recyclingand

retargetation

Waste tanks

Vacuumtank

CuOoven

Dissolver

I-se

para

tion

AGI

U

U + FP

U + Mo-99Mo-99

+ FP


Chel

ex

AGI

1 2 3 4

Subli-mationM

nO2 Activity


Decontaminationand

final treatment




3


3accompanied






2and CaCO

3added to the









Proc

ess

start

evac

uatio

n

Coo

ling

Coo

ling

Coo

ling

Coa

l filte

r

Wat

erco

nden

ser CuO

oven

VT1

VT2

VT3

SVT

Dropletcollector

Dissolver

Chem

ical

solu

tions

Cell 2

Iner

t gas

ldquoheli

umrdquo


MoIodine

Feed

AG1

-1co

lum

n

Ag2O















U4+ + 2H2O 999447999472 UO

2

2++ 4H+ + 2e + 0338V

H2O2+ 2H+ + 2e 999447999472 2H

2O + 177V



I +H2O 999447999472 HIO +H+ + 2e + 099V

(1)




2F2+HI + 2HF (2)


U3Si2+ 18HF + 6H

2O2997888rarr 3UO

2F2+ 2H2SiF6+ 6H2

(3)








minusprecipitate





3

minusHNO3








2SO4is needed to





2SO4Under


6]minus3 The Mo-










Safe

ty v

ac t

ank

H2-oxid

KOH

KOHKOH

HFaddH2O

DissolverFuel

precipi-tation

Xenon separation

HF

was

h


HeN2HeN2






3through the column










3



3

minusCO3








3

minusCO3



60

50

40

30

20

10

0

0 1 2 3

(gU

L)

MCO3

minus2


minus2

concentrations









minusCO3


3

minusCO3



10

20

30

40

50

60

70

80

90

100

Loading Washing

20 40 60 80 100 20 40 60 80 100

(mL)

Ce-144B(

)




minusCO3




100

80

60

40

100 200 300 400

Resin (gUkg)

R(

)

Bio-Rex5


minusCO3

minus2





100

80

60

40

20

1 2 3

Column volume [U]

Bio-Rex5

EU


Brea

kthr

ough

()

100

80

60

40

20

00 1 2 3 4 5 6 7 8 9 10

Loadingflowrate

Column volume [I]


Ru-106 994Sb-125 1000Uran 38

Elution(002m HNO3)

Washing(3m HNO3)
















3from the Bio-











3O8


4













Mix

oxi

de

Char

coal

Char

coal Cu

O

Vacu

um ta

nk

Dissolver

Iodineseparation

AG1times

8

MnO

2

Chel

ex-100

AG1times

4 Sub

I131prod


FE production

UF4 U3O8

WasteWaste

Waste Waste Waste

TBP

Iodinepurificproc

Bio-

Rex5

prodMo-99

Chimney

U-metal

U3Si2

(NH4)2U2O7










Filtration

Filtration

Filtration








U3Si2




sim90 of Mo-99

sim10 of Mo-99

sim90 of Mo-99

sim10 of Mo-99

UAlx


3Si2fueled targets






119909-based



3 Conclusions






















119909and U

3Si2 In case of



Acknowledgment


References






































FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of


















Mix

oxi

de

Char

coal

Char

coal

Char

coal

To cellventilation

H2Ocond CuO


Iodineseparation

AG1times

8

MnO

2

Chel

ex-100

AG1times

4 Sub

I131prod

prod


FE production

UAl3 UF4 U3O8

WasteWaste

Waste Waste Waste

TBP

Iodinepurificproc

Bio-

Rex5

Mo-99

(NH4)2U2O7


Irradiation

Recyclingand

retargetation

Waste tanks

Vacuumtank

CuOoven

Dissolver

I-se

para

tion

AGI

U

U + FP

U + Mo-99Mo-99

+ FP


Chel

ex

AGI

1 2 3 4

Subli-mationM

nO2 Activity


Decontaminationand

final treatment




3


3accompanied






2and CaCO

3added to the









Proc

ess

start

evac

uatio

n

Coo

ling

Coo

ling

Coo

ling

Coa

l filte

r

Wat

erco

nden

ser CuO

oven

VT1

VT2

VT3

SVT

Dropletcollector

Dissolver

Chem

ical

solu

tions

Cell 2

Iner

t gas

ldquoheli

umrdquo


MoIodine

Feed

AG1

-1co

lum

n

Ag2O















U4+ + 2H2O 999447999472 UO

2

2++ 4H+ + 2e + 0338V

H2O2+ 2H+ + 2e 999447999472 2H

2O + 177V



I +H2O 999447999472 HIO +H+ + 2e + 099V

(1)




2F2+HI + 2HF (2)


U3Si2+ 18HF + 6H

2O2997888rarr 3UO

2F2+ 2H2SiF6+ 6H2

(3)








minusprecipitate





3

minusHNO3








2SO4is needed to





2SO4Under


6]minus3 The Mo-










Safe

ty v

ac t

ank

H2-oxid

KOH

KOHKOH

HFaddH2O

DissolverFuel

precipi-tation

Xenon separation

HF

was

h


HeN2HeN2






3through the column










3



3

minusCO3








3

minusCO3



60

50

40

30

20

10

0

0 1 2 3

(gU

L)

MCO3

minus2


minus2

concentrations









minusCO3


3

minusCO3



10

20

30

40

50

60

70

80

90

100

Loading Washing

20 40 60 80 100 20 40 60 80 100

(mL)

Ce-144B(

)




minusCO3




100

80

60

40

100 200 300 400

Resin (gUkg)

R(

)

Bio-Rex5


minusCO3

minus2





100

80

60

40

20

1 2 3

Column volume [U]

Bio-Rex5

EU


Brea

kthr

ough

()

100

80

60

40

20

00 1 2 3 4 5 6 7 8 9 10

Loadingflowrate

Column volume [I]


Ru-106 994Sb-125 1000Uran 38

Elution(002m HNO3)

Washing(3m HNO3)
















3from the Bio-











3O8


4













Mix

oxi

de

Char

coal

Char

coal Cu

O

Vacu

um ta

nk

Dissolver

Iodineseparation

AG1times

8

MnO

2

Chel

ex-100

AG1times

4 Sub

I131prod


FE production

UF4 U3O8

WasteWaste

Waste Waste Waste

TBP

Iodinepurificproc

Bio-

Rex5

prodMo-99

Chimney

U-metal

U3Si2

(NH4)2U2O7










Filtration

Filtration

Filtration








U3Si2




sim90 of Mo-99

sim10 of Mo-99

sim90 of Mo-99

sim10 of Mo-99

UAlx


3Si2fueled targets






119909-based



3 Conclusions






















119909and U

3Si2 In case of



Acknowledgment


References






































FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of



















3


3accompanied






2and CaCO

3added to the









Proc

ess

start

evac

uatio

n

Coo

ling

Coo

ling

Coo

ling

Coa

l filte

r

Wat

erco

nden

ser CuO

oven

VT1

VT2

VT3

SVT

Dropletcollector

Dissolver

Chem

ical

solu

tions

Cell 2

Iner

t gas

ldquoheli

umrdquo


MoIodine

Feed

AG1

-1co

lum

n

Ag2O















U4+ + 2H2O 999447999472 UO

2

2++ 4H+ + 2e + 0338V

H2O2+ 2H+ + 2e 999447999472 2H

2O + 177V



I +H2O 999447999472 HIO +H+ + 2e + 099V

(1)




2F2+HI + 2HF (2)


U3Si2+ 18HF + 6H

2O2997888rarr 3UO

2F2+ 2H2SiF6+ 6H2

(3)








minusprecipitate





3

minusHNO3








2SO4is needed to





2SO4Under


6]minus3 The Mo-










Safe

ty v

ac t

ank

H2-oxid

KOH

KOHKOH

HFaddH2O

DissolverFuel

precipi-tation

Xenon separation

HF

was

h


HeN2HeN2






3through the column










3



3

minusCO3








3

minusCO3



60

50

40

30

20

10

0

0 1 2 3

(gU

L)

MCO3

minus2


minus2

concentrations









minusCO3


3

minusCO3



10

20

30

40

50

60

70

80

90

100

Loading Washing

20 40 60 80 100 20 40 60 80 100

(mL)

Ce-144B(

)




minusCO3




100

80

60

40

100 200 300 400

Resin (gUkg)

R(

)

Bio-Rex5


minusCO3

minus2





100

80

60

40

20

1 2 3

Column volume [U]

Bio-Rex5

EU


Brea

kthr

ough

()

100

80

60

40

20

00 1 2 3 4 5 6 7 8 9 10

Loadingflowrate

Column volume [I]


Ru-106 994Sb-125 1000Uran 38

Elution(002m HNO3)

Washing(3m HNO3)
















3from the Bio-











3O8


4













Mix

oxi

de

Char

coal

Char

coal Cu

O

Vacu

um ta

nk

Dissolver

Iodineseparation

AG1times

8

MnO

2

Chel

ex-100

AG1times

4 Sub

I131prod


FE production

UF4 U3O8

WasteWaste

Waste Waste Waste

TBP

Iodinepurificproc

Bio-

Rex5

prodMo-99

Chimney

U-metal

U3Si2

(NH4)2U2O7










Filtration

Filtration

Filtration








U3Si2




sim90 of Mo-99

sim10 of Mo-99

sim90 of Mo-99

sim10 of Mo-99

UAlx


3Si2fueled targets






119909-based



3 Conclusions






















119909and U

3Si2 In case of



Acknowledgment


References






































FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of


















Proc

ess

start

evac

uatio

n

Coo

ling

Coo

ling

Coo

ling

Coa

l filte

r

Wat

erco

nden

ser CuO

oven

VT1

VT2

VT3

SVT

Dropletcollector

Dissolver

Chem

ical

solu

tions

Cell 2

Iner

t gas

ldquoheli

umrdquo


MoIodine

Feed

AG1

-1co

lum

n

Ag2O















U4+ + 2H2O 999447999472 UO

2

2++ 4H+ + 2e + 0338V

H2O2+ 2H+ + 2e 999447999472 2H

2O + 177V



I +H2O 999447999472 HIO +H+ + 2e + 099V

(1)




2F2+HI + 2HF (2)


U3Si2+ 18HF + 6H

2O2997888rarr 3UO

2F2+ 2H2SiF6+ 6H2

(3)








minusprecipitate





3

minusHNO3








2SO4is needed to





2SO4Under


6]minus3 The Mo-










Safe

ty v

ac t

ank

H2-oxid

KOH

KOHKOH

HFaddH2O

DissolverFuel

precipi-tation

Xenon separation

HF

was

h


HeN2HeN2






3through the column










3



3

minusCO3








3

minusCO3



60

50

40

30

20

10

0

0 1 2 3

(gU

L)

MCO3

minus2


minus2

concentrations









minusCO3


3

minusCO3



10

20

30

40

50

60

70

80

90

100

Loading Washing

20 40 60 80 100 20 40 60 80 100

(mL)

Ce-144B(

)




minusCO3




100

80

60

40

100 200 300 400

Resin (gUkg)

R(

)

Bio-Rex5


minusCO3

minus2





100

80

60

40

20

1 2 3

Column volume [U]

Bio-Rex5

EU


Brea

kthr

ough

()

100

80

60

40

20

00 1 2 3 4 5 6 7 8 9 10

Loadingflowrate

Column volume [I]


Ru-106 994Sb-125 1000Uran 38

Elution(002m HNO3)

Washing(3m HNO3)
















3from the Bio-











3O8


4













Mix

oxi

de

Char

coal

Char

coal Cu

O

Vacu

um ta

nk

Dissolver

Iodineseparation

AG1times

8

MnO

2

Chel

ex-100

AG1times

4 Sub

I131prod


FE production

UF4 U3O8

WasteWaste

Waste Waste Waste

TBP

Iodinepurificproc

Bio-

Rex5

prodMo-99

Chimney

U-metal

U3Si2

(NH4)2U2O7










Filtration

Filtration

Filtration








U3Si2




sim90 of Mo-99

sim10 of Mo-99

sim90 of Mo-99

sim10 of Mo-99

UAlx


3Si2fueled targets






119909-based



3 Conclusions






















119909and U

3Si2 In case of



Acknowledgment


References






































FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of























minusprecipitate





3

minusHNO3








2SO4is needed to





2SO4Under


6]minus3 The Mo-










Safe

ty v

ac t

ank

H2-oxid

KOH

KOHKOH

HFaddH2O

DissolverFuel

precipi-tation

Xenon separation

HF

was

h


HeN2HeN2






3through the column










3



3

minusCO3








3

minusCO3



60

50

40

30

20

10

0

0 1 2 3

(gU

L)

MCO3

minus2


minus2

concentrations









minusCO3


3

minusCO3



10

20

30

40

50

60

70

80

90

100

Loading Washing

20 40 60 80 100 20 40 60 80 100

(mL)

Ce-144B(

)




minusCO3




100

80

60

40

100 200 300 400

Resin (gUkg)

R(

)

Bio-Rex5


minusCO3

minus2





100

80

60

40

20

1 2 3

Column volume [U]

Bio-Rex5

EU


Brea

kthr

ough

()

100

80

60

40

20

00 1 2 3 4 5 6 7 8 9 10

Loadingflowrate

Column volume [I]


Ru-106 994Sb-125 1000Uran 38

Elution(002m HNO3)

Washing(3m HNO3)
















3from the Bio-











3O8


4













Mix

oxi

de

Char

coal

Char

coal Cu

O

Vacu

um ta

nk

Dissolver

Iodineseparation

AG1times

8

MnO

2

Chel

ex-100

AG1times

4 Sub

I131prod


FE production

UF4 U3O8

WasteWaste

Waste Waste Waste

TBP

Iodinepurificproc

Bio-

Rex5

prodMo-99

Chimney

U-metal

U3Si2

(NH4)2U2O7










Filtration

Filtration

Filtration








U3Si2




sim90 of Mo-99

sim10 of Mo-99

sim90 of Mo-99

sim10 of Mo-99

UAlx


3Si2fueled targets






119909-based



3 Conclusions






















119909and U

3Si2 In case of



Acknowledgment


References






































FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of


















Safe

ty v

ac t

ank

H2-oxid

KOH

KOHKOH

HFaddH2O

DissolverFuel

precipi-tation

Xenon separation

HF

was

h


HeN2HeN2






3through the column










3



3

minusCO3








3

minusCO3



60

50

40

30

20

10

0

0 1 2 3

(gU

L)

MCO3

minus2


minus2

concentrations









minusCO3


3

minusCO3



10

20

30

40

50

60

70

80

90

100

Loading Washing

20 40 60 80 100 20 40 60 80 100

(mL)

Ce-144B(

)




minusCO3




100

80

60

40

100 200 300 400

Resin (gUkg)

R(

)

Bio-Rex5


minusCO3

minus2





100

80

60

40

20

1 2 3

Column volume [U]

Bio-Rex5

EU


Brea

kthr

ough

()

100

80

60

40

20

00 1 2 3 4 5 6 7 8 9 10

Loadingflowrate

Column volume [I]


Ru-106 994Sb-125 1000Uran 38

Elution(002m HNO3)

Washing(3m HNO3)
















3from the Bio-











3O8


4













Mix

oxi

de

Char

coal

Char

coal Cu

O

Vacu

um ta

nk

Dissolver

Iodineseparation

AG1times

8

MnO

2

Chel

ex-100

AG1times

4 Sub

I131prod


FE production

UF4 U3O8

WasteWaste

Waste Waste Waste

TBP

Iodinepurificproc

Bio-

Rex5

prodMo-99

Chimney

U-metal

U3Si2

(NH4)2U2O7










Filtration

Filtration

Filtration








U3Si2




sim90 of Mo-99

sim10 of Mo-99

sim90 of Mo-99

sim10 of Mo-99

UAlx


3Si2fueled targets






119909-based



3 Conclusions






















119909and U

3Si2 In case of



Acknowledgment


References






































FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of




















3



3

minusCO3








3

minusCO3



60

50

40

30

20

10

0

0 1 2 3

(gU

L)

MCO3

minus2


minus2

concentrations









minusCO3


3

minusCO3



10

20

30

40

50

60

70

80

90

100

Loading Washing

20 40 60 80 100 20 40 60 80 100

(mL)

Ce-144B(

)




minusCO3




100

80

60

40

100 200 300 400

Resin (gUkg)

R(

)

Bio-Rex5


minusCO3

minus2





100

80

60

40

20

1 2 3

Column volume [U]

Bio-Rex5

EU


Brea

kthr

ough

()

100

80

60

40

20

00 1 2 3 4 5 6 7 8 9 10

Loadingflowrate

Column volume [I]


Ru-106 994Sb-125 1000Uran 38

Elution(002m HNO3)

Washing(3m HNO3)
















3from the Bio-











3O8


4













Mix

oxi

de

Char

coal

Char

coal Cu

O

Vacu

um ta

nk

Dissolver

Iodineseparation

AG1times

8

MnO

2

Chel

ex-100

AG1times

4 Sub

I131prod


FE production

UF4 U3O8

WasteWaste

Waste Waste Waste

TBP

Iodinepurificproc

Bio-

Rex5

prodMo-99

Chimney

U-metal

U3Si2

(NH4)2U2O7










Filtration

Filtration

Filtration








U3Si2




sim90 of Mo-99

sim10 of Mo-99

sim90 of Mo-99

sim10 of Mo-99

UAlx


3Si2fueled targets






119909-based



3 Conclusions






















119909and U

3Si2 In case of



Acknowledgment


References






































FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of


















10

20

30

40

50

60

70

80

90

100

Loading Washing

20 40 60 80 100 20 40 60 80 100

(mL)

Ce-144B(

)




minusCO3




100

80

60

40

100 200 300 400

Resin (gUkg)

R(

)

Bio-Rex5


minusCO3

minus2





100

80

60

40

20

1 2 3

Column volume [U]

Bio-Rex5

EU


Brea

kthr

ough

()

100

80

60

40

20

00 1 2 3 4 5 6 7 8 9 10

Loadingflowrate

Column volume [I]


Ru-106 994Sb-125 1000Uran 38

Elution(002m HNO3)

Washing(3m HNO3)
















3from the Bio-











3O8


4













Mix

oxi

de

Char

coal

Char

coal Cu

O

Vacu

um ta

nk

Dissolver

Iodineseparation

AG1times

8

MnO

2

Chel

ex-100

AG1times

4 Sub

I131prod


FE production

UF4 U3O8

WasteWaste

Waste Waste Waste

TBP

Iodinepurificproc

Bio-

Rex5

prodMo-99

Chimney

U-metal

U3Si2

(NH4)2U2O7










Filtration

Filtration

Filtration








U3Si2




sim90 of Mo-99

sim10 of Mo-99

sim90 of Mo-99

sim10 of Mo-99

UAlx


3Si2fueled targets






119909-based



3 Conclusions






















119909and U

3Si2 In case of



Acknowledgment


References






































FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of




























3from the Bio-











3O8


4













Mix

oxi

de

Char

coal

Char

coal Cu

O

Vacu

um ta

nk

Dissolver

Iodineseparation

AG1times

8

MnO

2

Chel

ex-100

AG1times

4 Sub

I131prod


FE production

UF4 U3O8

WasteWaste

Waste Waste Waste

TBP

Iodinepurificproc

Bio-

Rex5

prodMo-99

Chimney

U-metal

U3Si2

(NH4)2U2O7










Filtration

Filtration

Filtration








U3Si2




sim90 of Mo-99

sim10 of Mo-99

sim90 of Mo-99

sim10 of Mo-99

UAlx


3Si2fueled targets






119909-based



3 Conclusions






















119909and U

3Si2 In case of



Acknowledgment


References






































FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of


















Mix

oxi

de

Char

coal

Char

coal Cu

O

Vacu

um ta

nk

Dissolver

Iodineseparation

AG1times

8

MnO

2

Chel

ex-100

AG1times

4 Sub

I131prod


FE production

UF4 U3O8

WasteWaste

Waste Waste Waste

TBP

Iodinepurificproc

Bio-

Rex5

prodMo-99

Chimney

U-metal

U3Si2

(NH4)2U2O7










Filtration

Filtration

Filtration








U3Si2




sim90 of Mo-99

sim10 of Mo-99

sim90 of Mo-99

sim10 of Mo-99

UAlx


3Si2fueled targets






119909-based



3 Conclusions






















119909and U

3Si2 In case of



Acknowledgment


References






































FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of




















Filtration

Filtration

Filtration








U3Si2




sim90 of Mo-99

sim10 of Mo-99

sim90 of Mo-99

sim10 of Mo-99

UAlx


3Si2fueled targets






119909-based



3 Conclusions






















119909and U

3Si2 In case of



Acknowledgment


References






































FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of































119909and U

3Si2 In case of



Acknowledgment


References






































FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of




































FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of





















FuelsJournal of







Advances in



Journal of


Renewable Energy





RotatingMachinery


EnergyJournal of

















Documents

Research Article Production Cycle for Large Scale Fission Mo ...downloads.hindawi.com/journals/stni/2013/704846.pdfScience and Technology of Nuclear Installations Mix. oxide Charcoal